a) Field of the Invention
The invention is directed towards a device of the type which moves a window casement between a closed and an open position with respect to a stationary window frame by means of a longitudinally displaceable toothed rack. In order to do this, a driving pinion is rotatably mounted in the frame, which engages with the toothed rack, and which, for example, can be rotatably operated by means of a crank handle.
b) Description of the Related Art
In the known device of this type (US-PS 1 671 362) the carrier is connected in a fixed manner to the toothed rack and has a slit with which a tongue with a guide pin, fixed onto the casement, engages. To ensure the closed position of the casement, at least one pair of closing elements with mutually complementary closing elements has to be arranged between the casement and the frame. An additional handle is necessary to transfer the moveable closing elements of these pairs from their latched position, in which they keep the casement in the frame, into an unlatched position, in which the casement is released. An additional space on the casement or on the frame is required for this handle. As the rotary operation of the driving pinion must be carried out to coincide with the operation of the handle, the manipulation of this known device was awkward. Faulty operation could occur, leading to damage to the components.
In a device of another type (DE-OS 41 09 852), a lever perpendicular to the plane of the frame of the window frame is pivoted by means of a crank mechanism to move the casement, and the lever is connected to the casement in an articulated manner by means of a connecting rod. A rod for moving the pairs of casing elements is arranged in the casement and connected to the connecting rod. The moveable closing elements of these pairs of closing elements are arranged on the casement, while the associated stationary closing elements are located on the window frame. Although the closing elements on the casement side are also moved between their latching and unlatching positions by means of the crank mechanism, this changing over is done by means of the connecting rod, that is to say the same member used for moving the casement between its open and closed positions. The rod for moving the closing elements is arranged in line with the members used for moving the casement, that is the pivoting lever and the connecting rod. In order to eliminate faulty operation, the rods for moving the closing elements in the casement must be blocked by a stop which is rendered inoperative when the casement comes into contact with the frame. This necessitates additional manufacturing and assembly costs. The arrangement of the stop on the casement takes up space.